Carburetor



Dec. 21 1926. 1,611,347

A. E. HARTWEYLL v CARBURETOR Filed Nov. 25, 1919 Patented Dec. 21, 1926.;

UNITED STATES PATENT OFFICE.

ALBERT n. mar-WELL, or new roux, 1w. Y., Assrenon r auro'nn'rrnannnr conroaa'rron, or' nnwanx, new JERSEY, a conronarron or ELAWARE,

GARBUBETOB.

Application filed November 25, 1919. Serial at. 340,594.

The general object of the" invention is to provide a simple, durable and reasonably mexpensive instrument which proportions the fuelto the air with varying operative con itions. A. more particular object is to provide means acted upon both by the throttle; and by an element moved by the current of air passing through the instrument to regulate the fuel supply very accurately in accordance with the osition of the throttle and the varying speeds of the point of substantially the greatest veloc-' ity of the air stream to insure the proper eduction and atomization of the fuel under all conditions and particularly at the lower engine speeds, and also to maintain a substantial pressure diii'erential in the 'instru:

ment at all times, and especially at the lower engine speeds, so that fuel ma be drawn to the point of utilization int e instrument from a lowdowntank (whensuch a tank arrangement is desired) without the inter-' position of any fuel pump or other fuel feed device, and without a float chamber. Other objects are realized in the mechanical embodiment of the invention as sufficient-- 1y explained hereinafter. The accompanyin representative embo' iment of the invention. After considering this in connection with the description, persons skilled in the art will understand how the invention may be embodied in other forms.

Figure 1 is a side elevation of a carburetor embodying the invention.

Fig. 2 is a vertical section in 'a plane I r parallel to Fig. 1 and,

" Fig. 3 is a vertical section in the transverse what diagrammatic, its plane for illustrative purposes being made to pass through the throat valve and fuel supply tube.

reat accuracy under drawing shows one" neL,

lane of Fig. 1, this view being some- The body 1 has the usual flange 2 for at .6 tachment t0 the intakev manifold. At two opposite sides the body is provided with openings and these openings are closed by side plates 3 and 4 attached by, screws 5. The cross sectional shape of an intermediate part. of the instrument is preferably substantiall rectangular and theopenings and cover p ates permit the instrument to be properly formed in this shape and also per-- mit the interior to be machined to the extent that is necessary or desirable.

-The usual throttle 6 is located in an upper part of'the instrument a'ndthis throttle is carried on a shaft 7. The usual lever arm 8 for connection to footand hand controlling devices is mounted on one end of theshaft. 7

Below'the throttle is a movableselement 9 acting upon and actuated by the air stream. ThlS element may for identification becalled an air valve. It is usually of substantially rectangular outline and its sides fit with suit able closeness to the detachable side plates .3 and 4. The air valve is providedwith a base enlargement or hub 10 having an aperture which provides an oscillating, bearing for the valve upon the reduced inner end of fuel tube 12. This fuel tube has a screw thread 13 seated in an internal thread in a cylindricalrboss ,14 formed on side plate 3,

and the tube also has anenlarged head 15 which may be in the form of a nut; The

tube has a central boreg16, and lateral holes 17 are drilled through it near the head '15 H to communicate with an annular channel 18 formed aboutthe tube at this point. A connection for fuel from any suitable tank to the fuel tube is provided conveniently by a fitting 19 which has a part 20 adapted to receive any standard fuel line connection 0 member, and also has a rin shaped part 21 surrounding the annular c annel 18. The fitting has a passage 22 leading to the chan In assembling the instrument the fuel tube is' passed through the ring 21 of the fitting. and then screwed into the boss 14. The fitting maybe placed in any convenient position to receive the fuel line connection and then secured to make the fuel conduit 7 fuel-tight by screwing the tube in firmly. The inner end of the fuel tube fits Wlthll'l, the aperture in the valve hub.

, Substantially centrally located in the air valve is a passage 23 leading from the hub aperture to a point where the passage is intersectedby a transverse channel 24 formed by drilling laterally through the valve near its free edge. The channel 24 is also intersected by a thin slot 25 which may be conveniently formed by means of a very thin circular saw or milling cutter. The ends of transverse channel 24 are closed by plugs 26. By the channels and slot just described, a fuel orifice extending entirely across the free edge of the air valve is formed in a simple way.

The portion 30 of the hub aperture of the air valve extending toward the side opposite from the fuel tube is of enlarged diameter. At the inner end of the enlarged portion 30 ofithe hub aperture islocated a short cylindrical cam body 31 which is fixed in position to move with the air valve 9 by a pin 32. Revolubly mounted in aperture 30 and in line with the cam body 31 is another cylindrical cam body, or sleeve 33. The confronting annular'faces of the cam body 31 and sleeve 33 are formed into cooperating cam surfaces, or in other words, these confronting faces of the two cylindrical bodies may be cut on an angle which will produce one suitable form of cam surfaces for the purpose in view. Relative rotary movement of the two cam bodies caused by their connection with the air valve 9 and with the throttle respectively, as later moreparticularly explained, will cause the 'cam sleeve or body 33 to move axially away late 4. This boss'is bored to provide a caring for the larger .part of sleeve 33 and is formed with an inwardly extending shoulder 37 and a light spring 38 is com ressed between shoulder 34 of the sleeve an shoulder 37 of the boss and accommodated in the recess provided between the sleeve and the boss at this point This spring serves to retain sleeve 33 in position with the cam faces on elements 31 and 33 abutting while permitting it to move in and out to adjust the fuel orifice as explained below. Sleeve 33 and cam 31 are bored through centrally and a needle valve 40, usually identified as the fuel valve, extends through this bore and is adjusted by means of a. screw thread 41 engaging an internal thread formed in the outer part of the bore. The tapered inner end 42 of the needle valve constituting the fuel valve proper cooperates with the inner end of the fuel tube to regulate the amount of fuel permitted to pass from the tube to the fuel nozzle 25. The fuel valve has a knurled head 43.

An arm 45 is connected to the outer end of sleeve 33 usually bymeans of a split clamp 46. This clamp permitsthe angular position of the arm to be easily adjusted .cam to rotate in accordance with the movement of the throttle for reasons later described.

The hub 10 of air valve 9 is provided with an arm which usually extends substantially at a right angle from-the valve proper. This arm is connected by a link 51, with a slide or plunger 52 located in a hollow screw 53 "which in-turn is seated in a cylindrical boss 54 of the carburetor body. A spring 55 is located in the hollow screw and opposes the inward movement of the plunger. Tension of the spring is-adjusted by turning screw 53. I

The location and arrangement of the air valve may vary considerably and so also with regard to the interior parts of the carburetor bodywhich cooperate with the valve to form the mixing space or part of the air channel adjacent to the fuel nozzle But in a preferred arrangement, as shown, the air valve usually lies, when closed, at a moderate angle above the horizontal and rests upon a part of the'carburetor body which may be identified in some cases as a ledge, and preferably-this ledge or stop for the outer end of the'valve' lies between a curved inner surface 61 of the air passage leading to the air valve and a curved inner surface 62 leading away from the valve, these surfaces being designed to direct the air current in natural lines of flow so far as possible. An adjustable stop 63 may be provided when necessary or desirable to limit the opening movement of the air valve.

The lower portion of the carburetor body may be provided witha bend 65 as shown, and the intake end 66 may be arranged to receive a hot air connection. A butterfly valve 67 may also'be provided'to admit an adjustable amount of cold air at some point below the mixing space.

It is frequently desirable to provide convenient means operable from the drivers position for retracting the fuel valve toadmit an increased amount of fuel, for instance in starting. For this purpose the needle valve may be provided with an eye 70, and to this may be connected a flexible wire or cord 71 leading to the dash of the car in which the carburetor is installed, or to any by spring 38.

other suitable location. This cord is arranged to have normally a moderate amount so arranged does not 1nof slack, and when terfere with the normal operation of the instrument. When the cord is-pulled however the slack is taken up and the needle valve with its sleeve 33 are pulled out sutiiciently to give an extra flow of fuel for starting priming.

In the position of parts shown in Fig. 2 the air passage is completely closed by the air valve which is .held upon its ledge or seat ,60 by spring 55 acting through link"51. The throttle is closed and-through the link connection 48 sleeve 33 is held in such a position thatits cam surface is so positioned in relation to cam 31 that the sleeve and needle valve are held in their innermost position The fuel valve 40 'is adjusted to give the desired amount of fuel for idling. When it is desired to start the engine the throttle is opened more or less. This throttle movement acts through link 48 to rotate sleeve 33. Cam 31 is held still by its connection with the air valve. The cam surface on sleeve 33 acting on cam 31 causes the sleeve to move outward to an extent which has a certain ratio to the degree of throttle opening, and thus the fuel valve is opened wider to a corresponding extent. When the engine begins to rotate the air pressure above the air valve is reduced very materially'before the valve begins to move.

. This creates a. powerful suction at the fuel orifice and draws an ample supply of fuel for starting through the orifice, channel 23',

the tube passage. 16, and the fuel line. The reduction of pressure is ample to draw fuel properly from the rear tank of a vehicle even when it is located as far below the fuel nozzle as it is possible to locate such a tank in a motor vehicle. At this moment the spring and itslinkage are in position to exert the maximum degree of resistance to opening movement of the air valve. The described condition having persisted for an appreciable fraction of time, the air valve opens under the pressure of atmospheric air to an extent depending upon the amount of throttle opening and the speed of the engine. A constriction is thus formed between the edge of the-air valve and shoulder and the air column at this point has the highest velocity that it. reaches anywhere in the instrument. This rapidly moving air jet passes smoothly around the curved surface 62 toward the throttle and in doing so is mixed with fuel issuing from the fuel outlet, this supply of fuel being distributed entirely across the air stream at a point imme diately adjacent to the throat, or point of highest velocity. Spring 55 causes the air valve to malntaln a resistance to the air,-

this resistance decreasing however in proportion to the amount of opening of the valve, since as the valve opens the arm 50 and link 51 come more nearly'into line and have substantially a toggle action. This to a great extent overcomes the added resistance of the spring as it is compressed and also tends toreduce the resistance to the movement of air at the higher speeds, slncethe speed of the engine and the amount of air passing through the throat as indicated by the position of the air valve. With the engine running under its own power, if the same throttle adjustment is maintained, the amount and speed .of air passin through the instrument will vary in accor ance with the speed of the engine, which in turn depends uponthe load. The air valve will be correspondingly positioned by the air flow and in each of its positions the fuel cams 31 and 33 will position the fuel valve properly to deliver the proper proportion of fuel for the engines .speed.

In each opening movement of the throttle the fuel supply is increased ahead of the response by the air valve to the increased engine speed, assuming that the engine speeds up in proportion to the increased opening of the throttle. A richer propor tion of'fuel is thus supplied and the missing or slow acceleration of the engine which -fre quently occurs in ordinary practice due to failure to get sufficient fuel for the increased air supply as the throttle is opened Wider, is avoided. As soon as the engine speeds up or he amount of air passing the valve increases to the normal amount for the throt tle setting the air valve opens wider to a corresponding extent, and the fuel supply is cut down by the interaction of the fuel cams 31 and 33 to the normal amount for that throt- -tle setting and engine speed.

of the closing movement of the air valve.

This avoids flooding and choking frequently experienced in ordinary practice due to the continued flow of fuel under inertia when the throttle is quickly closed. As soon as the engine speed adjusts itself-to. the new condition the closing movement of the air valve reopens the fuel valve somewhat, so as to properly proportion the fuel for the new running condition.

When throttle arm 47 is considerably shorter than sleeve arm 45, as above de-; scribed, and when theangular positions of the arms on their shaft and sleeve respectively are as'shown in Fig. 1, that is with arm 47 substantially horizontal and arm tilted upward at a substantial angle to l1ori-- opening of \the throttle is relatively less as the throttle opening increases.v To suit different operative conditions the interaction between the throttle and the fuel valve may be varied by adjusting the angular positions of arms 45 and 47.

The organization of the instrument is such that a sufficiently reduced pressure is main-.

tained at the fuel nozzle at all times to draw fuel from a low tank and at the same time the interaction of the regulating elements is such as to prevent an excess supply of fuel at any of the different running points.

I c aim:

1. In a carburetor, the combination of a body providing an air passage, a throttle, an air valve below the throttle acted upon by the air current, a fuel orifice discharging in the vicinity of the air "alve, a fuel controlling valve, means acting upon opening movement of the throttle tending to open the fuel valve, and means acting upon opening movement of the air valve tending to close the fuel valve.

2. A carburetor for internal combustion engines, comprising a body providing an air passage, an air valve movably mounted in the passage and arranged for direct actuation by the air stream and to provide a varying aperture in accordance with the flow of-air depending on variations in engine speed, a throttle, a fuel aperture in the air passage, a valve to control the supply of fuel to the aperture, a cam member connected to move with the air valve and a cooperatlng cam member connected to move with-the throttle, the cam members acting upon the fuel valve to regulate the fuel opening in accordance with both the throttle position and the flow of air.

3. A carburetor for internal combustion engines, comprising a body providing an air passage, an air valve movably mounted in the passage and arranged for direct actua-4 tion by the air stream and to provide a varying aperture in accordance with the flow of air depending on variations in engine speed,

a throttle, a fuel aperture in the movable air valve, a valve to control the supply of fuel to the aperture, a cam member connected to move with the air valve and a cooperating cam member connected to mo've with the throttle, the cam members acting upon the fuel valve to regulate the fuel opening in accordance with both the throttle position and the fiow of air. 7

4. A carburetor for internal combustion engines, comprising a body providing an air passage, an airvalve movably mounted in the passage and arranged for direct actuation by the air stream and to provide a varying aperture in accordance with the flow of air depending on variations inengine speed, means for opposing varying resistance to the opening movement of the air valve, the resistance decreasing as the valve opening increases, a throttle, a fuel aperture in the air passage,-a' valve to control the supply of'fuel to the aperture, a cam member connected to move wlththe air-valve and a cooperating cam member connected to move with the throttle, the cam members acting upon the fuel valve to regulate the fuel opening in accordance with both and the fiow of air.

5. In a carburet-or,'thev combination of a body having an airpassage, a throttle therein, an air actuated-valve in the air passage and pivotally mounted near one side thereof, the air valve having a long narrow fuel orifice near its free edge and a, fuel, passage leading to the orifice, a fuel tube leading through the pivot axis of the valve to said passage, a fuel valve seat located in the fuel tube, a fuel valve co-operating with the seat, and means actuated by the co-operative movement of the air valve and throttle to position 'the fuel valve.

6. In a carburetor, the combination of a body providing an air passage, an oscillatable air valve, a fuel tube extending into and providing abe'aring for the air valve, a cam fixed in the air valve coaxially with the fuel. tube, a sleeve rotatably mounted in respect to the air valve and coaxiai with the fuei tube, said sleeve having a cam surface to cooperate with said cam, a throttle above the air valve, a throttle shaft, an arm on said shaft; an arm on said sleeve, a link connecting the arms, and a fuei valve carried by the sleeve and arranged to cooperate with a valve-seat provided in the air valve.

7. In a carburetor, the combination of a body providing an air passage, an oscillatable'air valve, a'fuel tube extending into and providing a bearing for the air valve, a cam fixed in the air valve coaxially with the fuel tube. a sleeve rotatably. mounted in respect to the air valve and coaxial with the fuel tube, said sleeve having a cam surface to cooperate with said cam, means retaining the sleeve yieldably in position, a throttle the throttle position body providing an air passage, an oscillatable air valve, a fuel tube extending into and; providing a bearing for the air valve, a cam fixed in the air valve coax'ially with the fuel vtube, a sleeve rotatably mounted in respect to the air valve and coaxial with the fuel tube, said sleeve having a cam surface to. co-. operate with said earn, a throttle above the air valve, a throttle shaft, an arm on said shaft, an arm on said sleeve, a link connecting the arms, a fuel valve carried by'the sleeve and arranged to cooperate with a valve-seat provided in the air valve, an arm extendin from the air valve near its .pivot axis, a plunger arranged to reciprocate toward and from the pivot axis, a spring resisting movement of the plunger, and a link connecting the plunger with said arm of the air valve.

. 9. In a carburetor, the combination of a body providing an air passage. an oscillatable alr valve, a fuel tube extending into and providing a bearing for the air va ve, a cam fixed in the-air valve coaxially with the fuel tube, a sleeve rotatably mounted in respect to the air valve and coaxial with the .fuel

tube, said sleeve having a cam surface to cooperate with said cam, a throttle above the throat valve, a throttle shaft, an arm on said shaft, an arm on said sleeve, a link connecting the arms, a fuel valve carried by the sleeve and arranged to cooperate with a valve-seat provided in the air valve, the air valve being provided near its upper edge with a thin fuel orifice extending substantlally the width of the valve, and a fuel passage leading from the orifice to a point of communication with the fuel orifice controlled by said fuel valve.

10. In a carburetor, the combination of a body providing an air passage, an oscillatable air valve, a fuel tube extending into and providing a bearing for the air valve, a cam xed in. the air valve coaxially with the fuel tube, a sleeve rotatably mounted in respect to the air valve and coaxial with the fuel tube, said sleeve having a cam surface to cooperate with said cam, a throttle above the air valve, a throttle shaft, an arm on said shaft, an arm on said sleeve, a link connecting the arms, a fuel valve carried by the sleeve and arranged to cooperate with a valve-seat provided in the air valve, the air passage belng provided with a ledge to cooperate with the air valve, and with curved surfaces leading to and from the ledge.

ALBERT E. HARTWELL. 

